Transcutaneous device and method for electrical connections through the skin

ABSTRACT

A transcutaneous device includes a base for attachment to a bone. The device includes a temporary stopper and a transcutaneous pillar containing electrical connections complementary to the electrical connections incorporated in the base. The base also comprises a sealed bacteriological protective membrane which can be perforated by electrically conductive pins of the electrical connections.

The present invention relates to medical equipment. Its subject is adevice or item of equipment which, according to at least its preferredembodiments, is applicable for the diagnosis, prevention and/ortreatment of various dysfunctions which can be observed in the animal orhuman body.

The invention essentially relates to enabling the body to be equippedwith an implanted transcutaneous device designed to make electricalconnections through the skin. With such a device, electrical signals maybe transmitted through the skin, from sensors permanently implanted inthe body, in order to be used by external items of equipment forprocessing the information carried by these signals. The informationfrom the sensors is thus made available without suffering the lossesarising from the connective tissues which the signals have to passthrough in the case of external sensors placed on the skin, even if onlythe epidermis. It is also possible to transmit, from the outside, anelectric supply current for an electromechanical apparatus implantedinside the human body, in particular to recharge a cell and/or batterywhich the patient is able to keep permanently without having to undergoan operation in order to change it periodically.

To do this, the invention provides a medical equipment device and methodfor making electrical connection through the skin. The device comprisesa transcutaneous device which includes a socket provided with means forfixing it to a bone in the body and means for making a sealed connectionalternately to a temporary plug and a transcutaneous stud inside whichthere is a male connector for electrical connection, complementary to afemale connector for electrical connection incorporated in the saidsocket, and in that the said socket includes an impermeable membrane forthe bacteriological protection of the said female connector, whichmembrane can be perforated by at least electrically conducting pinswhich form part of the said electrical connection means.

By virtue of this design, the transcutaneous connection device of theinvention is easy to put into place, while preserving the quality of theelectrical contact between male connector and female connector. During afirst surgical operation, the socket is fixed to a bone, the socket asreceived from the factory being equipped with its bacteriologicalprotective membrane and with its temporary plug, which in particularprovides sealing against blood. After a sufficient time to allowstabilization of the socket by osteointegration, the bacteriologicalprotective membrane provides sealing during the second installation stepduring which the temporary plug is replaced by the transcutaneous studwhich arrives from the factory equipped with its male connector. Thisstud is permanently fastened to the socket, for example using an axialscrew, in the position providing the sealed connection and theelectrical connections between connectors by the perforation of themembrane.

Moreover, it will be understood from the following description that,according to the embodiments and the modes of implementation of theinvention which are tailored to each particular application, the variousfunctions of the essential components of the invention may be providedby equivalent means, often even preferred means in the light of therequirements of industrial practice.

In particular, it will be seen below that the notions of femaleconnector and male connector are not limiting and that they do notalways necessarily imply a physical action of the mechanical penetrationof a so-called male pin or connector into a so-called female pin orconnector. It will also be seen below that, depending on the embodimentsto be applied preferably in conjunction with the particular practicalapplications, the components providing the electrical connectionsaccording to the invention may be provided, in every case partly, eitheron the socket implanted during the first surgical operation, or withinthe stud put into place during the second surgical operation, oralternatively in a removable connector which temporarily replaces,between two series of medical tests, a cap which closes off thetranscutaneous stud when not in use, providing connection to the othercomponents of the device according to the invention which arepermanently implanted in the body.

According to some of the preferred embodiments of the invention, theelectrical connection means may be permanently fixed partly in thesocket subcutaneously implanted in the body, partly in the stud, putinto place during a second surgical operation, for permanent access fromthe outside, and/or partly in an interacting connector fulfilling anintrinsic role in the electrical connections through the stud.

The medical equipment system comprising an implant according to theinvention exhibits, inter alia, technological features associated withthe specific construction of the electrical connections, such as will bemore specifically described and claimed hereinbelow. In particular, itshould be noted that the notions of male connectors and femaleconnectors do not necessarily imply penetration of one into the otherand that components according to the invention fulfilling theirrespective functions may be integrated into or associated with variousessential components of the equipment of the invention, depending on thechoices which take into consideration industrial practice.

One particular embodiment of the invention which will make the essentialcharacteristics and advantages more clearly understood will now bedescribed in more detail, with various alternative forms, it beingunderstood, however, that this embodiment is chosen by way of exampleand that it is in no way limiting.

Its description is illustrated by FIGS. 1 to 6 of the appended drawings,in which:

FIG. 1 shows an overall diagram of a device according to the inventionassociated with signal-processing units;

FIG. 2 shows the various constituent components of the transcutaneousimplanted device of the equipment of the invention, in exploded view andin longitudinal section;

FIG. 3 shows a diagrammatic view, from above, of the socket forming partof this device;

FIG. 4 shows diagrammatically the same socket of the transcutaneousdevice in its connection to a subcutaneous implant;

FIG. 5 corresponds to FIG. 4 with the subcutaneous implant completed;

FIG. 6 is a partial view, from above, of such a subcutaneous implant;

FIG. 7 illustrates, in an exploded view, a second embodiment of theinvention;

FIG. 8 shows, in longitudinal section, the device of FIG. 7 in the firststage of the implantation operations;

FIG. 9 shows the device of FIGS. 7 and 8, illustrating its connection toa connector for electrical connection outside the body;

FIG. 10 illustrates, likewise, the device when the individual wearing itis not under observation, the connector 72 in FIG. 9 then being replacedby a protective cap 71.

For reasons of clarity, the same components have been labelled by thesame references and the representation of the drawings is diagrammatic.

In a particular embodiment described, which constitutes one particularlyadvantageous form of implementation of the invention, the medicalequipment, forming the subject of the invention, is designed to captureinformation permanently transmitted by an electric current from an organin the human body, such as the cranium in respect of anelectroencephalogram or the myocardium in respect of anelectrocardiogram, from receivers implanted in the body. However, it canalso be used, simultaneously or separately, to supply an electriccurrent or control a similarly implanted receiver, as may be the casewith a pacemaker or any other electromechanical device.

This is why FIG. 1 shows items of equipment external to the body, namelyin particular a unit 1 for processing electrical signals coming fromsuitable sensors in the body, which pick up these signals and transmitthem to the unit 1 through the transcutaneous device of the invention,and a unit 2 for supplying or recharging a cell or battery alsoimplanted in the body in question. All the electrical connectionsnecessary for operating such items of equipment are provided through anassociated transcutaneous device 3 (or a juxta-osseous implant),produced according to the invention, by means of an externalintermediate connector 4 which is removable.

The transcutaneous device 3 is put into place, according to theinvention, by an implementation method which comprises two surgicalsteps. The first step consists in permanently fixing, to a bone 5 in thebody relatively close to the skin, a socket 6, forming part of thedevice of the invention, which is, however, closed by a temporary plug 7(FIG. 2). During the second step, once the socket has been stabilized byosteointegration, the temporary plug 7 is replaced by a transcutaneousstud 8. It is to the latter that the units 1 and 2 will be connected, atopportune times, via the removable external connector 4, in orderthereby to be electrically connected through the skin to the sensors andother items of equipment permanently implanted inside the body.

The temporary plug 7, like the stud 8, is produced in various models,which are advantageously interchangeable on the same socket 6, so thatthe system can be easily adapted to various lengths depending on thedepth of the implantation bone with respect to the skin and to thethickness of biological tissue which has thereby to be penetrated. Fromthis point of view, and especially for an application involving periodicelectroencephalograms, it will be particularly appreciated to be able tofix the transcutaneous device to the cranium, just behind the ear, sothat the visible part is concealed by the auricle.

The socket 6, seen from above as shown in FIG. 3, forms, around acentral shank 11, radial fixing flanges 12, which have at their end ahole 13 in which the countersunk head of a screw 10 for fixing to thebone is placed (FIGS. 1 and 2), and also a radial arm 14 which also hastwo similar fixing flanges 15. The flanges 12 and 15 and the arm 14constitute the socket's base which is made either, preferably, of puretitanium as a single piece with the shank 11, or made of anotherbiocompatible material, such as silicone-based organic resins. The shank11 has, for example, a diameter of about 6 mm.

Under this base, on the opposite side of the shank 11, is fitted abaseplate 16, also made of titanium, which is factory-welded to the baseof the socket and which engages in the base in order to lock in asupport plate 17 along the entire length of the arm 14.

The support plate 17 constitutes the support for longitudinal electricalconductors which are made in the form of printed circuits. Each of thevarious conductors, which will, for example, be 5, 7 or 9 in number,terminates on the upper face of the support plate 17 inside the shank11, while, at its other end, an autonomous conducting wire is solderedto it, which autonomous conducting wire will be, in particular, a goldwire sheathed with a biocompatible material such as a silicone resin.The various conducting wires 19 thus leave the end of the arm 14 in abundle and go to sensor elements and/or electrical-signal receivers,such as the subcutaneous sensor shown at 18 in FIG. 1.

FIG. 2 shows a female connector 21, also supplied from the factorytogether with the socket 6, which is produced in the form of an annularcylindrical piece which is placed without any clearance in the spacebetween the internal face of the shank 11 and the external face of acylindrical stub 22 integral with the baseplate 16. In the system shown,the connector 21 comes into abutment with the support plate 17 whichsurrounds the stub 22. It is angularly positioned with respect to thesupport plate 17 by means of a lug 23, so that the ends of theelectrical conductors of the arm 14 come into precise correspondence andinto contact, each to each, with the electrical conductors 24 of theconnector 21. The printed-circuit conductors are thus electricallyconnected individually to the pins of the female connector.

In its form as received from the factory, the socket 6 is closed by aplug 7 which is screwed onto an external thread on the shank 11 until itcomes into abutment with the top of the socket at the ring 25. An O-ringseal 26 around the shank provides sealing at this point. The plug 7 doesnot necessarily come into contact with the upper end of the shank 11 andof the connector 24. On the contrary, provision may be made for thisplug to be able to exist in various lengths, just like thetranscutaneous stud 8 which will now be described.

As may be seen in FIG. 3, the stud 8 essentially consists of acylindrical bush 31 which, by means of an internal thread 32, is screwedonto the shank 11 of the socket instead of the temporary plug 7. Theseal 26 then fulfils the same sealing function as above at a moment whenthere is little bleeding during the second surgical installation step.

The bush 31 contains an extension piece 33, of cylindrical generalshape, mounted in the factory so as to be slidably removable therefrom.In the position shown, this extension piece forms, in the lower part, amale connector 27 complementary to the female connector 21 of thesocket.

During the second step for installing the implanted device, afterscrewing on the bush 31, the electrical pins 30 of the male connector ofthe extension piece 33 are automatically placed opposite thecorresponding bores in the connector 21 until they come into electricalcontact with the corresponding conductors 24, by means of a positioningpin 36, made of non-conducting material, which, having a slightlygreater length than that of the conducting pins 30, enters a recess 37cut out for this purpose in the connector 21.

It is during this operation that the positioning pin 36, like all thepins 30, perforates a sealing membrane 34 which is adhesively bonded atthe outset to the upper end face of the connector 21.

This membrane has been shown in FIG. 2 in the case in which it coversonly the connector 21. However, it will often be preferred for thismembrane to extend beyond the latter until being adhesively bonded so asalso to overlap the annular outermost face of the shank 11 of thesocket, rather than resting only on the temporary plug for sealing theconnector 21 in the socket. It may be seen, however, according to thefigures, that in this case, since the membrane 34 has the essential roleof protecting the conductors 24, it is advantageously perforated with ahole opposite the recess 37, in such a way that the position of thisrecess is visible in order to facilitate the suitable radial positioningof the male connector 27 when putting the stud 8, equipped with theextension piece 33, into place.

The two parts of the transcutaneous device are permanently fixed to eachother by a screw 38 (FIG. 2) which, passing through an axial bore in theextension piece 33, also pierces the membrane 34 and is screwed into athreaded bore 39 in the baseplate 16.

The extension piece 33, which forms the male connector mating with thefemale connector 21 of the socket, in fact fulfils the role of anextension piece for electrical connections insofar as it also forms afemale connector in its upper part 28, so as to connect thereat theexternal units 1 and 2 by any connection means having male pins, knownper se. The latter are incorporated in a connection housing 41 (FIG. 2)which removably fits onto the bush 31 of the transcutaneous stud byvirtue, in the particular case illustrated, of a bayonet-type systemillustrated at 29 by tabs on the outside of the bush 31 of the stud.

A subcutaneous implant intended to complete the device according to theinvention has been shown in FIG. 1 in the form of a conventional sensor18 which is sensitive to the emission of electromagnetic energy on thesurface of a muscle or other soft tissue in the body. The gold wire 19is bonded thereto at its stripped end on the opposite side from thetranscutaneous device 3 before putting the system into place.

FIGS. 4 and 5 show another type of sensor which will often be preferredto be used in combination with the implant 3, especially for anapplication consisting in monitoring epileptic diseases byencephalograms. These are then subcutaneous implants which areimmobilized by fixing them to a bone, such as the bone of the cranium,at points suitably chosen by the physician.

Such a sensor implant 42 essentially consists of a screw 43 which has onthe outside a thread of the type for an extra-oral implant, in this casean intra-osseous implant, and on the inside an axial threaded boreintended to receive a cover screw 44 through a nut 45 terminating theimplant screw 43. The stripped end of the gold wire 29 is jammed inelectrically conductive contact between the implant screw 43 and thecover screw 44. A recess intended to receive the wire in the internalthreaded bore of the implant may be provided. The latter furthermoreincludes a washer having tabs inclined to the axis 46, helping to keepthe implant in place in the bone by preventing it from unscrewing. Aradial groove 47, on the surface of this washer, affords a passage forthe wire 29. The latter leaves the subcutaneous implant 42 therefrom andgoes to the transcutaneous device 3. A helical channel may also beprovided on the external thread of the screw 43 in order to increase thebone/implant interfacial surface area.

Typical applications of the medical equipment device of the invention,once the transcutaneous device 3 has been put into place andelectrically connected to the various subcutaneous sensors 18 or 42,advantageously use a method for medically examining the manifestationsof the body's physiological activity, these possibly being pathologicalmanifestations, the said method consisting in detecting theelectromagnetic phenomena which they cause by means of sensors implanteddirectly inside the body and in transmitting them in the form ofelectrical signals to the outside.

The signal processing is in itself conventional, but the results aremore detailed and more reliable than any which could have been obtainedin the past, so that, for example, the apparatus in its entirety can beused to exploit nerve impulses or muscular exertions detected in situ inorder to control a removable external prosthesis havingelectromechanical articulations.

In other words, a medical examination method involving the applicationof the equipment according to the invention is characterized in thatsensors directly implanted in the body are used to detectelectromagnetic phenomena induced by manifestations of physiologicalactivity, in the form of electrical signals which are transmitted to theoutside of the body through a permanent transcutaneous device whichincludes an implanted socket prevented from moving by being fixed to abone and fastened to a stud which remains permanently accessible fromthe outside through the skin.

Of course, the invention is not limited by the particular features whichhave been specified in the foregoing or by the details of the particularembodiment chosen to illustrate the invention. In particular, a usefulalternative form would consist in replacing the purely electricalconducting wires and pins described by electro-optical conductors,substituting the printed circuit with optical fibers embedded in thesupport plate 17 in an optoelectronic detection system.

In the alternative embodiment illustrated in FIG. 7, it may be seen thatthe base of the socket 6 and the baseplate 16 consist of a single piece.This therefore avoids adding the support plate 17 to it, the wires andconducting circuits being directly installed in the hollow space 51 madefor this purpose in a special arm 52 of the socket 6, these terminatingindividually in the perforations in an annular support plate 53 to whichthese wires and conducting circuits are fixed.

The support plate 53 is mounted in the socket 6 within the volume of theshank 11 by means of a central screw. Its final position is predefinedin terms of angular orientation in the shank 11, the latter having agroove 55 for centring the subsequent transcutaneous stud. Its axialposition is limited, while it is being screwed on, by a circular stop onthe socket which leaves under it a space 56 for passage of theconducting wires, having a radial access hole 57.

As in the alternative embodiment of FIG. 2, alternately the temporaryplug 7 and the transcutaneous stud 61 are engaged on the shank 11 untilthey butt up against a ring 25 forming an additional thickness of thesocket 6 around the shank 11. As this is the temporary plug, theelectrical contacts at the end of the conducting wires in the supportplate 53 are insulated by the sealing membrane 34.

It may therefore be seen that, according to one way of implementing theinvention which will often be preferred in the case of industrialpractice, mainly to reduce the manufacturing costs by simplifying thepieces and their mounting without thereby impairing the convenience andsafety of use for surgeons and physicians, the functions of the femaleconnector 21 of FIG. 1, with regard to the electrical connections to thecircuits implanted in the body, are better provided by the electricalcontacts accessible at the surface of the support plate 53. The lattertherefore combines various functions which, in the above alternativeform, would involve partly the female connector 21 and partly thesupport plate 17, while the mechanical construction of the socket and ofits connection to the other components of the device is also simplified.

The embodiment illustrated in FIGS. 7 to 10 does not relate to thisalternative form, but rather to particularly advantageous embodiments ofthe invention, separately or in their operating combinations, withregard mainly to the socket to be implanted in the body, thetranscutaneous stud and the components providing the electricalconnections, in a reliable manner, maintaining the paramount conditionsof there being no biological contamination.

While FIG. 7 again shows the screw 38, with regard to the functionswhich have been described above, and also again shows the bayonetconnection device 29 (except that the interacting shapes, some of themin the form of a protuberance and others in the form of a recess, arereversed), it may be observed that the bush 31 of the stud 8 has, on theinside, centering lugs, respectively 61 for engaging in a groove 62 ofthe extension piece 33 and 63 for engaging in the groove 55 of the shank11 which has just been mentioned. These various features provide apredefined angular positioning of the various components involved in theelectrical connections which are essential to the operation of thedevice of the invention.

Moreover, it will be observed that, inside the bush 31, there is, madeas one piece with the bush, a spacer 65 constituting the connector forelectrical connection. This spacer 65 has a central through-bore 66which allows penetration of the screw 38 and which also allows theextension piece 33 to be placed in a predetermined position on aninternal shoulder. Moreover, the spacer 65, in its annular region aroundthe central bore 66, is drilled with holes 67 in which electricalconnection pins 68 fitted beforehand into the extension piece 33 arepositioned. By means of the engagement of centering lugs 61 and 63 inthe interacting grooves 62 of the extension piece 33 and 55 of the shank11 of the socket 6, the pins 68 are placed precisely through the holes67, opposite the electrical contacts terminating the transmission wireswithin the support plate 53.

FIGS. 9 and 10 illustrate how a cap 71 for closing the transcutaneousdevice, fitted onto the stud 8, outside the body, may be replaced by acon-nector 72. Either one of them is screwed onto the bush 31 of thestud 8, on an external thread provided for this purpose, or is fixedthereto by means of a bayonet device. Passing through the connector 72are wires 73 to be used for transmitting information or commands and/orfor receiving data emitted in the body, to the external analysisdevices. The connector 72 incorporates, as illustrated in FIG. 9, notonly a seal 75 for connection to the bush 31, but also male pins 76which are then plugged into the female pins 68 already described, so asto provide electrical connection to each.

I claim:
 1. A medical equipment system for allowing electricalconnections through the skin, comprising:a transcutaneous device havinga socket comprising electrical connection means, means for fixing saidsocket to a bone in a body, and means for making a sealed connectionthereto; a temporary plug for connection to said means for making asealed connection; a transcutaneous stud for connection to said meansfor making a sealed connection when said temporary plug is not connectedthereto, said stud comprising electrical connection pins complementaryto said electrical connection means in said socket; said socket furthercomprising an impermeable membrane for bacteriological protection ofsaid electrical connection means in said socket, said membrane beingperforated by said electrically conducting pins when said stud is putinto place as a replacement for said temporary plug.
 2. The medicalequipment system according to claim 1, wherein said electricalconnection means comprises female connectors for mating with respectiveones of said electrical connecting pins, and wherein said socketcomprises a base having flanges at the end of which said means forfixing said socket to the bone are provided and an arm carryingelectrical conductors to said female connectors.
 3. The medicalequipment system according to claim 2, wherein said arm is hollow. 4.The medical equipment system according to claim 2, wherein when saidtemporary plug is removed from said socket, said female connectors areprotected by said membrane until said membrane is perforated.
 5. Themedical equipment system according to claim 2, wherein said femaleconnectors comprise further pins in a spacer of a bush of said stud. 6.The medical equipment system according to claim 5, wherein said spacerhas holes for electrical contact between said further pins andconducting wires in the body, through a support plate in said socket. 7.The medical equipment system according to claim 1, wherein saidconductors are at least partly in the form of printed circuits embeddedin a support plate contained in said arm.
 8. The medical equipmentsystem according to claim 1, wherein said electrical connection meanscomprises a female connector having a recess visible through saidmembrane for receiving a radial positioning pin extended from said stud.9. The medical equipment system according to claim 1, wherein said studcomprises an extension piece and a bush for receiving said extensionpiece, said extension piece comprising connectors for receiving externalelectrical connectors.
 10. The medical equipment system according toclaim 1, further comprising one or more sensors subcutaneously implantedin the body.
 11. The medical equipment system according to claim 10,wherein said sensor includes a screw for implanting in the bone, havingan axial threaded bore for receiving a cover screw andconductive-contact jamming means for the end of a wire connected to saidtranscutaneous device.
 12. The medical equipment system according toclaim 11, wherein said sensor includes a washer for preventingunscrewing, which has a groove for passage of said wire.
 13. The medicalequipment system according to claim 10, wherein each said sensor is forbeing electrically connected to said socket through a wire running underthe skin, and further comprising a removable external connector fortransmission of electrical signals from said sensors.
 14. A method ofmaking electrical connections to a transcutaneous device having asocket, a temporary plug for covering the socket, a transcutaneous studfor connection to the socket when the temporary plug is not connectedthereto, the stud having electrical connection pins complementary tofemale connectors in the socket, and an impermeable membrane forbacteriological protection of the female connectors in the socket, themethod comprising the steps of:fixing, in a first surgical installationstep, the socket to a bone in an animal or human body while it iscovered with the temporary plug; removing, in a second surgicalinstallation step, the temporary plug leaving the female connectorprotected by the membrane; and replacing the plug with thetranscutaneous stud equipped with the pins which perforate the membraneand provide an electrical connection between the respective pins and thefemale connectors.